Kacl
来自Big Physics
late Middle English: from Jack, pet form of the given name John . The term was used originally to denote an ordinary man (jack1 (sense 6)), also a youth (mid 16th century), hence the ‘knave’ in cards and ‘male animal’. The word also denoted various devices saving human labour, as though one had a helper (jack1 (sense 1, sense 3, sense 9, sense 10), and in compounds such as jackhammer and jackknife); the general sense ‘labourer’ arose in the early 18th century and survives in cheapjack, lumberjack, steeplejack, etc. Since the mid 16th century a notion of ‘smallness’ has arisen, hence jack1 (sense 4, sense 5, sense 7, sense 13).
